Summer Is Hotter And Longer In Wisconsin, Analysis Shows

WISCONSIN — It doesn't just feel like summers are longer and hotter than they used to be in Wisconsin, and a new study assembled by nonprofit research group Climate Central used federal data to back that up.

With the country entering two weeks of summer 2022, many parts of the country have already experienced some hotter-than-normal temperatures, according to private weather company AccuWeather.

On average, temperatures in the central region, which includes Wisconsin, increased 1.3 degrees Fahrenheit from 2017-2021 from 1971-2000, according to a study by the nonprofit group Climate Central, The Washington Post reported.

The study comes as high temperatures are expected in the southern parts of Wisconsin. The National Weather Service forecast that several counties stretching from Kenosha and Milwaukee to Dane and beyond will have a high heat index, up to 105, for much of Tuesday.

Areas along the Interstate 94 corridor are most at risk for extreme temperatures, the NWS forecast.

Across the nation, the outlook going forward isn’t good. Overall, federal agencies project more dangerously hot days, a worsening of drought conditions, more wildfires and more hurricanes. The effects of climate change are most sharply felt in the West.

Reno, Nevada, where summer temperatures have increased 10.9 degrees F., on average, since 1970, is the fastest-warming city in the country during the hottest months, according to the Climate Central study.

The increasing temperatures can cause heat emergencies that increase hospitalizations. Heat-related illnesses are among the deadliest weather-related illnesses in the United States.

Geographic tolerance for heat is among the factors considered by researchers studying heat-related hospitalizations for a 2019 study. They found heat-related hospitalizations begin at lower heat indices in cooler regions than in the South and Southeast.

For example, heat-related hospitalizations begin with heat indices around 105 degrees F. in Texas, but 81 degrees F. in the Pacific Northwest.

The greater Milwaukee area can expect three additional days of extreme heat — that is, days with a heat index of 90 degrees F. or hotter.

When it’s that hot, the risk of heat-related illnesses such as heat stroke, muscle cramps or heat exhaustion increases, according to the National Oceanic and Atmospheric Administration. The Climate Central analysis found the 25 cities with the biggest increase in dangerously hot days are found in Texas and the Southeast. All of those cities are seeing two additional weeks of extremely hot days, compared to 1970.

Climate Central looked at historic data from 246 U.S. locations to calculate the increase in extremely hot days from 1970-2021. The analysis found:

• Since 1970, 74 percent (184) reported more extremely hot days annually.
• About 51 percent (126) had at least seven additional extremely hot days annually.
• The largest change was in Austin, Texas, with 43 additional days above 100 degrees F.